Evaluation of bio control potential of AgNPs synthesized from Trichoderma viride Sambasivam Manikandaselvi 1,4 , Vembaiyan Sathya 1 , Vellingiri Vadivel 2 , Natarajan Sampath 3 and Pemaiah Brindha 2 1 Post-Graduate and Research Department of Biochemistry, Sengamala Thayaar Educational, Trust Women’s College, Mannargudi, Tamil Nadu, India 2 Centre for Advanced Research in Indian System of Medicine, SASTRA Deemed University, Thirumalaisamudram, Thanjavur, Tamil Nadu, India 3 School of Chemical and Biotechnology, SASTRA Deemed University, Thirumalaisamudram, Thanjavur, Tamil Nadu, India E-mail: selvithinagar@gmail.com Received 22 December 2019 Accepted for publication 3 April 2020 Published 25 June 2020 Abstract Currently, there is a global effort to reduce the use of harmful substances, particularly chemical pesticides in cultivation. The biological mechanism of soil-borne phytopathogens has proven to be a good alternative to the use of chemical pesticides. In recent times, synthesis of nanoparticle from fungus is a trustworthy and sustainable method. The current study explores the synthesis of silver nanoparticles (AgNPs) using Trichoderma viride (T. viride), non-pathogenic fungi isolated from soil. The isolates were confirmed by morphological characters. The cell filtrate of isolates of T. viride was used for the formation of AgNPs from silver nitrate. The synthesised AgNPs were characterised by using UV, XRD, FTIR, SEM and zeta potential analyser. The SEM images indicated that the nanoparticles were spherical and irregular-like in shape and polydispersed in size. XRD analyses were performed to check the crystal-like nature of nanoparticles. Zeta potential study confirms the stability of nanosuspension. In the present study, developed AgNPs of T. viride act as a suitable and persistent biocontrol agent against rice pathogenic fungi such as Rhizoctonia solani and Fusarium moniliforme and provide an improved opportunity for application in crop and disease controlling. Keywords: T. viride, AgNPs, biocontrol agent Classification numbers: 2.10, 4.02 1. Introduction Biocontrol agents should be in dynamic state in the correct place and at an exact time for successful disease control. The strategies used for the biocontrol of soil-borne pathogens include protection of the infection sites, impeding the pro- gress of pathogens in soil, and inactivation of surviving structures of the pathogen. Bio-agents that work through highly competitive ability or antibiosis are employed for protecting the infection court and restricting the growth of pathogen in the soil whereas the mycoparasites are often used for the destruction of surviving structures [1]. Mycoparasitism is a phenomenon of one fungus parasitising another fungus and is well known to occur in Trichoderma spp [2]. Myco- parasitism is a sequential and composite process, containing three stages as follows: Recognition-Trichoderma releases minor quantity of extracellular exochitinase attracted by the cell wall oligo- saccharides of the target fungi and endochitinase gene is sti- mulated while interacting with the target fungus. Eventually, the above changes stimulate the discharges of fungi toxic cell wall degrading enzymes from Trichoderma viz. extracellular hydrolytic enzymes for polysaccharides especially chitin, proteins, and lipids [3]. Coiling and interaction of hyphae-As Trichoderma recognised contact, it starts coiling around and forms a flat- tened hypha of a parasitic fungus that penetrates the host tissues for connection facilitated by polysaccharides from the | Vietnam Academy of Science and Technology Advances in Natural Sciences: Nanoscience and Nanotechnology Adv. Nat. Sci.: Nanosci. Nanotechnol. 11 (2020) 035004 (8pp) https://doi.org/10.1088/2043-6254/ab9d16 4 Author to whom any correspondence should be addressed. 2043-6262/20/035004+08$33.00 © 2020 Vietnam Academy of Science & Technology 1